Confocal microscopy after implantation of intrastromal corneal ring segments

OBJECTIVE: Confocal in vivo real-time microscopy was used to study the corneal morphologic features in eyes after Intrastromal Corneal Ring Segments (ICRS; now called KeraVision INTACS, KeraVision, Inc., Fremont, CA) implantation. DESIGN: Noncomparative, interventional case series. PARTICIPANTS: The authors performed confocal real-time microscopy on a total of 21 eyes from 11 patients. Seventeen eyes from 10 patients (five female, five male; mean age 32.3 years; range 22-42 years) underwent uncomplicated ICRS surgery to correct myopia and were examined after surgery (average 8.6 months; range 2-15 months). Three patients had the ICRS implanted into only one eye, and those eyes were compared with the untreated fellow eyes. One eye of another patient was examined 1 and 6 months after ICRS removal. INTERVENTION: Flying slit-confocal microscopy was performed with water immersion objectives in the corneal center and near the nasal or temporal ICRS. Corneal optical sections were recorded in real time without further digital processing and were reviewed frame by frame. MAIN OUTCOME MEASURES: Video frames selected from all corneal layers were evaluated qualitatively and quantitatively. RESULTS: In the central cornea, we found normal morphologic features at all layers. In peripheral sections, epithelial cells with highly reflective nuclei in the basal cell layer were observed in six of 17 eyes (35%) implanted with ICRS. We found an intact corneal nerve plexus and undisturbed corneal endothelium immediately underneath the ICRS. Around the ICRS, moderate fibrosis was seen. In one eye, linear structures in bamboo-like orientation were detected after ICRS removal in the last keratocyte layer underneath the collapsed tunnel. CONCLUSIONS: Whereas the central corneal zone appears unchanged, the corneal stroma adjacent to the ICRS displays a slight, but distinct, activation of wound healing. Epithelial cells with highly reflective nuclei in this region may be an indicator for an increased biologic stress caused by the device.     

Laser in situ keratomileusis and intrastromal corneal ring segments for high myopia. Three-step procedure

We describe a surgical procedure to correct relatively high myopia in patients with thin corneas. The technique combines laser in situ keratomileusis (LASIK) and intrastromal corneal ring segment (ICRS) implantation. The 3-step procedure comprises ICRS channel formation, LASIK, and segment insertion. The technique was used in 2 eyes of 2 patients with low pachymetry values and high myopia. One patient achieved an uncorrected visual acuity (UCVA) of 20/30 and a best spectacle-corrected visual acuity (BSCVA) of 20/25 with +0.50 -1.75 x 101. The other patient achieved a UCVA of 20/30 and a BSCVA of 20/20 with +0.75 -1.50 x 80.     

Central corneal pachymetry in patients undergoing laser in situ keratomileusis

OBJECTIVE: To report the preoperative ultrasonic central pachymetric measurements on a large group of eyes undergoing laser-assisted in situ keratomileusis (LASIK) surgery for myopia and myopic astigmatism, to determine whether central corneal thickness is correlated with other geometric features of the eye or is correlated with age or gender, and to discuss the resulting limitations on possible ablation depths. DESIGN: Prospective, multisite, cross-sectional study. PARTICIPANTS: Eight hundred ninety-six eyes in 450 patients from 21 to 66 years of age. MAIN OUTCOME MEASURES: Central corneal thickness and its correlation to intraocular pressure, corneal curvature, axial length, horizontal corneal diameter, refraction, age, and gender. RESULTS: The mean central corneal thickness was 550 microm with a standard deviation of 33 and a range of 472 to 651 microm. The lower 25th quantile was 528 microm. The central corneal pachymetry correlated with the mean manual keratometric measurement (P = 0.0001), simulated keratometry (Sim K) (P = 0.0001), and intraocular pressure (P = 0.0001). Central corneal thickness did not correlate with axial length, age, gender, horizontal corneal diameter, and refraction. CONCLUSION: This clinical study shows there is a substantial range of central corneal thickness in normal myopic eyes. With LASIK, there is a general concern that one should not thin the cornea further than a given amount. Because this study shows wide variability in central corneal thickness, it is prudent to measure pachymetry before surgery and gear treatment plans accordingly. Possible treatment limits relative to corneal thickness are discussed.     

Treatment of myopia and myopic astigmatism by customized laser in situ keratomileusis based on corneal topography

OBJECTIVE: To evaluate the predictability, efficacy, and safety of customized laser in situ keratomileusis (LASIK) based on corneal topography in myopia and myopic astigmatism. DESIGN: Prospective, noncomparative interventional case series. PARTICIPANTS: One hundred fourteen patients (eyes) with myopia of -1 to -6 diopters (D) and astigmatism of 0 to -4 D (low myopia group), and 89 patients (eyes) with myopia of -6.10 to -12.00 D and astigmatism of 0 to -4.00 D (high myopia group). INTERVENTION: LASIK was performed with the Hansatome Microkeratome and the Keracor 217 spot-scanning excimer laser (Bausch & Lomb Surgical Technolas, Munich, Germany). Individual ablation patterns were calculated on the basis of elevation data obtained with the Orbscan II corneal topography system (Bausch & Lomb Surgical, Irvine, CA). MAIN OUTCOME MEASURES: Manifest spectacle refraction, visual acuity, and change in visual acuity at 3 months after surgery. RESULTS: At 3 months, 51 patients in the low myopia group and 40 patients in the high myopia group were available. In the low (high) myopia group, 96.1% (75.0%) were within +/-0.50 D of emmetropia, and uncorrected visual acuity was 20/20 or better in 82.4% (62.5%), 20/25 or better in 98.0% (70.0%), and 20/40 or better in 100% (95.0%). A loss of two or more lines of spectacle-corrected visual acuity occurred in 3.9% of the low and 5. 0% of the high myopia group. In low myopia, spectacle-corrected visual acuity was 20/12.5 or better in 5.9% preoperatively and in 13.7% at 3 months and 20/15 or better in 37.3% and 47.1%, respectively. Differences were statistically significant. CONCLUSIONS: The customized LASIK based on corneal topography used in this study showed high predictability and efficacy in myopia and myopic astigmatism of -1.00 to -6.00 D, and could possibly improve spectacle-corrected visual acuity in myopia of -1.00 to -6.00 D. Predictability and efficacy were somewhat lower in myopia and myopic astigmatism of -6.10 to -12.00 D. In both groups, a small number of patients lost two or more lines of spectacle-corrected visual acuity.     

Evaluation of corneal stromal changes in vivo after laser in situ keratomileusis with confocal microscopy

PURPOSE: To assess by in vivo confocal microscopy the modifications of the corneal stroma after laser in situ keratomileusis (LASIK) for myopia. DESIGN: Nonrandomized comparative (self-controlled) trial. PARTICIPANTS: Sixteen eyes of 13 patients were examined before surgery and at days 8, 30, and 90, and 9 eyes were examined at 6 months postoperatively using an in vivo confocal microscope. TESTING/INTERVENTION: Stromal morphologic changes, keratocyte density, flap thickness, and subclinical haze were evaluated and compared at different time points. LASIK was performed with a Flapmaker microkeratome (Solan Ophthalmic products, Jacksonville, FL) and a Lasersight LSX excimer laser (LaserSight Technologies Inc., Winter Park, FL). MAIN OUTCOME MEASURE: Confocal microscopy results. RESULTS: Microfolds at the Bowman's layer were found in most eyes, as well as variable reflectivity particles (pa) located at the interface level in all eyes examined postoperatively. The density of these particles significantly decreased with time with, respectively, 504 +/- 101 pa/mm2 at day 8 and 380 +/- 111 pa/mm2 at day 30 (P = 0.003), 332 +/- 100 pa/mm2 at month 3 and 312 +/- 40 pa/mm2 at month 6. The mean flap and the activated-cells area thicknesses were, respectively, 102 +/- 26 microm and 61 +/- 19 microm and showed significant negative correlation (P < 0.0001). The intensity of the added peak (47.3 microm 8.6%), corresponding to the subclinical haze, realized by Z-scan measure, was also negatively correlated with flap thickness (P = 0.01). Keratocyte (k) density quantified in the posterior stroma significantly increased from day 0 (480 +/- 67 k/mm2) to day 8 (701 +/- 41 k/mm2, P < 0.0001 compared with day 0) and day 30 (917 +/- 143 k/mm2, P = 0.0006, compared with day 0) but significantly decreased at 3 months postoperatively (597 +/- 56 k/mm2, P < 0.0001 compared with day 30) to reach the initial level at month 6 (502 +/- 41 k/mm2, nonsignificant compared with day 0). There was no correlation between preoperative or postoperative spherical equivalent and the density of particles, keratocytes, and the haze intensity. CONCLUSIONS: This study confirms the presence of microfolds and particles at the interface level, as well as subclinical impairment. Evaluation of keratocyte density constitutes a major contribution of confocal microscopy toward an understanding of the keratocyte response to corneal wound healing after corneal refractive surgery. Moreover, flap thickness seems to be involved in the postoperative cellular activation with a higher response when thin.     

Laser in situ keratomileusis for correction of myopia and astigmatism after penetrating keratoplasty

Purpose

To determine the safety and effectiveness of laser in situ keratomileusis (LASIK) for visual rehabilitation of residual myopia and astigmatism after penetrating keratoplasty.

Mycobacterium interface keratitis after laser in situ keratomileusis

PURPOSE: To report the clinical course, management, and outcome of infectious interface keratitis caused by mycobacterium species after laser in situ keratomileusis (LASIK). DESIGN: A small noncomparative interventional case series. PARTICIPANTS: Five eyes in four patients who underwent LASIK in different locations around the world and had culture-positive mycobacterium keratitis develop. INTERVENTION: The LASIK flap was lifted or amputated, samples were submitted for Ziehl-Neelsen acid-fast stain and Lowenstein-Jensen's agar cultures for diagnosis; topical treatment with fortified clarithromycin and amikacin was administered until clinical resolution. MAIN OUTCOME MEASURES: Time periods from onset to diagnosis and from diagnosis to clinical resolution, and the final visual acuity. RESULTS: Onset of symptoms of infection occurred after a mean of 20 days (range, 11 days-6 weeks) after LASIK or an enhancement procedure. Definitive diagnosis was obtained after a mean period of 4.5 weeks (range, 12 days-8 weeks) from onset. Keratitis resolved within 8.4 weeks (range, 1-18 weeks) of treatment with fortified clarithromycin and amikacin. Corticosteroids were found to worsen and prolong the course of disease. In four of five eyes the LASIK flap was amputated. CONCLUSIONS: Mycobacterial keratitis is a potentially vision-threatening complication after LASIK, characterized by a long latent period, delayed diagnosis, and a protracted course even under intensive specific antibiotic therapy. Inclusion of specific culture media and staining protocols for mycobacteria, along with aggressive treatment on diagnosis, including lifting or amputating the LASIK flap, culturing, topical fortified clarithromycin and amikacin, while avoiding corticosteroids, may significantly improve resolution of the infection and potentially improve the visual outcome.     

Late traumatic dislocation of laser in situ keratomileusis corneal flaps

PURPOSE: To report the management and outcome of late-onset traumatic dislocation of laser in situ keratomileusis (LASIK) flaps. DESIGN: Retrospective, observational case series. PARTICIPANTS: Four patients with late-onset LASIK flap dislocation occurring after mechanical trauma at various intervals (10 days-2 months) after the procedure. INTERVENTION: In all cases of postoperative traumatic LASIK flap dislocation, the flap was refloated with scraping and irrigation of the underlying stromal bed within 12 hours of the injury. A bandage contact lens was placed, and a regimen including topical antibiotics and corticosteroids was instituted in all cases. MAIN OUTCOME MEASURES: Best spectacle-corrected visual acuity and complications associated with the surgery were monitored. RESULTS: Postoperative follow-up ranged from 4 to 21 months. Nonprogressive epithelial ingrowth was noted in one patient and diffuse lamellar keratitis developed in another patient. All patients recovered pretrauma spectacle-corrected visual acuity. CONCLUSIONS: Corneal LASIK flaps are prone to mechanical dislocation as late as 2 months after the procedure. Appropriate management results in recovery of optimal visual outcomes.     

Contrast sensitivity evaluation after laser in situ keratomileusis

OBJECTIVE: To determine the effects of laser in situ keratomileusis (LASIK) on best-corrected visual acuity (BCVA) and contrast sensitivity. DESIGN: Prospective, observational case series. PARTICIPANTS: One hundred twelve eyes, in 65 patients with myopia and myopia with astigmatism, who underwent LASIK. TESTING AND MAIN OUTCOME MEASURES: Best-corrected visual acuity using the Snellen visual acuity chart and contrast sensitivity using the CSV 1000 (Vector Vision, Dayton OH) was tested before surgery and 1 week, 1 month, and 3 months after surgery in patients who underwent LASIK. RESULTS: Contrast sensitivity was depressed for patient eyes with spherical equivalence (SE) between -1.25 diopters (D) and -13.75 D, at 12 cycles/degree for at least 3 months and at 18 cycles/degree for 1 week after LASIK. For patient eyes with SE between -1.25 D and -6.00 D, contrast sensitivity was depressed only at 12 cycles/degree for at least 3 months after LASIK. For patient eyes with SE between -6.00 D and -13.75 D, contrast sensitivity was depressed at 6, 12, and 18 cycles/degree 1 week after LASIK but returned toward preoperative levels by 1 month after surgery. Despite the slight decreases in contrast sensitivity, all scores were still within the range of normal values except for 12 cycles/degree for 3 months and 18 cycles/degree at 1 week after surgery in the high myopia group. Although highly myopic patients, compared with patients with low myopia, had slightly less BCVA before surgery, both groups maintained their preoperative BCVA at all postoperative visits. CONCLUSIONS: Based on this study, we conclude that LASIK has little effect on BCVA and contrast sensitivity for up to 3 months after surgery.     

Laser in situ keratomileusis (LASIK) in myopia: 2-year results

Background: Long-term results on LASIK are not available to date. We therefore evaluated the predictability, stability and complication rate after LASIK in moderate – to-high myopia. Patients and methods: We treated 70 eyes (41 patients) using the Automatic Corneal Shaper and the Keracor 116 excimer laser. Patients were followed for 1, 6, 12 and 24 months. Spectacle refraction, visual acuity, rate of retreatment, and patient satisfaction were evaluated. Results: At 24 months the results were as follows: Myopia −5 to −9.9 D (n =18): 94 % within 1 D; regression between 1 and 12 (12 and 24) months > 1 D in 6 % (6 %); uncorrected acuity 20/40 or better in 83 %; no loss of 2 ore more lines of visual acuity; 89 % highly satisfied. Myopia −10 to −14.9 D (n = 12): 88 % within 1 D; regression between 1 and 12 (12 and 24) months > 1 D in 20 % (0 %) ; uncorrected acuity 20/40 or better in 72 %; 4 % lost 2 or more lines of visual acuity; 96 % highly satisfied. Myopia −15 to −29 D (n = 22): 33 % within 1 D; regression between 1 and 12 (12 and 24) months > 1 D in 41 % (18 %); uncorrected acuity 20/40 or better in 7 %; no loss of 2 or more lines of visual acuity; 67 % highly satisfied. Conclusion: LASIK is an accurate, effective and stable procedure for correcting myopia of −5 to −10 D. Results are less precise in myopia up to −15 D, and some visual loss occurs in a number of patients. In myopia > −15 D, results are not satisfactory because of poor accuracy and low stability.      

Early results of hyperopic and astigmatic laser in situ keratomileusis in eyes with secondary hyperopia

PURPOSE: To assess the safety and efficacy of laser in situ keratomileusis (LASIK) for secondary hyperopia and hyperopic astigmatism and to develop a VISX STAR S2 LASIK nomogram (VISX Inc., Santa Clara, CA) for consecutive hyperopia after prior myopic refractive surgery. DESIGN: Prospective, nonrandomized, self-controlled interventional study. PARTICIPANTS: Thirty patients with consecutive hyperopia or hyperopia and astigmatism after LASIK, photorefractive keratectomy, automated lamellar keratoplasty, or radial keratotomy. INTERVENTION/METHODS: Prospective evaluation of LASIK in 30 secondary eyes with fogged manifest sphere from +0.5 to +6.0 diopters (D) and cylinder from 0 to +5.0 D. MAIN OUTCOME MEASURES: Uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA), and spherical equivalent (SE). RESULTS: Mean manifest SE was +1.73 +/- 0.79 D before surgery, -0.13 +/- 1.00 D at 6 months after surgery, and -0.18 +/- 1.08 D at 1 year after surgery. At 6 months, 84% of patients with secondary hyperopia had UCVA of 20/40 or better; 76% were within +/-1 D of emmetropia. At 1 year, 85% had UCVA of 20/40 or better and 85% were within +/-1 D of emmetropia. No patients with secondary hyperopia lost 2 or more lines of BCVA at 1 year. Complications included intraoperative bleeding (3.3%), intraoperative epithelial defect (3.3%), transient interface debris (3.3%), significant dry eye (3.3%), blood in interface (3.3%), irregular astigmatism (6.7%), slight decentration (6.7%), trace haze (6.7%), or mild epithelial ingrowth not requiring removal (3.3%). CONCLUSIONS: These early data suggest that LASIK for consecutive hyperopia from +0.5 to +5.50 D and astigmatism from 0 to +2.75 D using the VISX STAR S2 benefits from a nomogram adjusted for preoperative refraction, age, and prior refractive surgery, and is safe and effective.     

Evaluation of the onset and duration of effect of azelastine eye drops (0.05%) versus placebo in patients with allergic conjunctivitis using an allergen challenge model

OBJECTIVE: The trial evaluated the effectiveness of the investigational antihistaminic and antiallergic compound Azelastine Eye Drops (AZE) in the treatment of allergic conjunctivitis using an allergen challenge model. DESIGN: Randomized, double-blind, placebo-controlled, paired-eye study. PARTICIPANTS: Adults with a history of allergic conjunctivitis (>/=2 years) who were asymptomatic throughout the trial, had a positive skin test (cat dander, grass, or ragweed pollen within the last year), and had a positive conjunctival reaction (score 2+ or more for itching and redness in both eyes on a 0-4 scale) during two separate conjunctival provocation tests (CPT) before randomization. METHODS: Eighty patients underwent a 2-week screening period (visits 1 and 2) that included a CPT during visit 1 to establish the allergen threshold dose and a second confirmatory CPT performed at visit 2. Eye symptom assessments for itching (evaluated by patient) and conjunctival redness (evaluated by physician) were performed 5 and 10 minutes after CPT using a 5-point scale (from 0 = none to 4+ = severe). Qualified patients were randomized to receive one drop of AZE (0.015 mg of azelastine hydrochloride) in one eye and one drop of placebo in the other eye 20 minutes before CPT at visit 3 (onset) and 8 or 10 hours before CPT at visit 4 (duration). MAIN OUTCOME MEASURES: Individual severity scores for itching (evaluated by patient) and conjunctival redness (evaluated by physician) for each eye at 3, 5, and 10 minutes after CPT at visits 3 and 4 using a 5-point scale (0 = none to 4+ = very severe). RESULTS: Each of the 80 randomized patients completed the trial. Mean itching and conjunctival redness scores at visit 3 (onset) were significantly lower (P: < 0.001) in the AZE-treated eyes than in the placebo-treated eyes. At visit 4 (duration), mean itching and conjunctival redness scores (P: 相似文献   

飞秒激光制瓣LASIK术后泪膜变化及相关性分析

目的 观察飞秒激光制瓣准分子激光原位角膜磨镶术后泪膜的变化,BUT、泪液分泌试验和泪河高度的相关性.方法 临床病例系列研究.收集2013年8～9月长春爱尔眼科医院行飞秒激光制瓣LASIK术并随访3个月的患者120例(240只眼),观察术前、术后1周、1、2和3个月患者的荧光素检查的泪膜破裂时间(BUT)、Oculus角膜地形图仪检查的BUT、泪液分泌试验(S Ⅰ t)、Oculus角膜地形图仪检查的泪河高度(TMH)的变化,同时观察荧光素BUT和Oculus BUT、泪液分泌试验和Oculus泪河高度的相关性.结果 Oculus BUT:术后1周与术前相比有差异有统计学意义(P=0.00＜0.05),术后1、2、3个月与术前相比差异无统计学意义(P =0.556,0.663,0.087＞0.05).荧光素BUT:术前荧光素BUT与术后1周、l、2、3个月相比均差异有统计学意义(P =0.033,0.025,0.004,0.000＜ 0.05).Schirmer Ⅰ试验:术后1周、1个月与术前差异有统计学意义(P =0.000,0.002＜0.05),术后2、3个月与术前差异无统计学意义(P=0.776,0.753＞0.05).泪河高度:术后1周、1个月与术前相比差异有统计学意义(P =0.00＜0.05),术后2、3个月与术前相比差异无统计学意义(P =0.096,0.229＞0.05).Oculus BUT和荧光素BUT相关分析:相关关系为正相关.泪河高度和Schirmer Ⅰ相关分析:无相关关系.结论 飞秒激光制瓣准分子激光原位角膜磨镶术术后早期影响泪膜的稳定性;Oculus角膜地形图仪非侵入性BUT检查具有可靠性,重复性较好,可以作为临床干眼诊断的一个参考标准.     

Third (fourth and fifth) nonocular tumors in survivors of retinoblastoma

OBJECTIVE: This study aimed to investigate the incidence, timing, pattern, and distribution of, as well as survival as a result of, third, fourth, and fifth primary tumors in survivors of retinoblastoma. DESIGN: This study was a retrospective case series of patients diagnosed with retinoblastoma and a second malignant neoplasm. Records were examined for demographic, prior treatment, and second tumor information, as well as any evidence of the development of a third, fourth, or fifth nonocular tumor. When possible, telephone inquiries were conducted for follow-up. PARTICIPANTS: The study included 1506 patients followed in the Ophthalmic Oncology Center at New York-Presbyterian Hospital, New York Weill Cornell Medical Center, 211 of whom developed a second tumor and had sufficient treatment data to be useful for analysis. MAIN OUTCOME MEASURES: The development of third and additional nonocular tumors and survival from these tumors were the primary outcome measures. RESULTS: Of 211 second-tumor patients, 142 died before an additional malignancy developed (median survival time, 1.8 +/- 0.3 years) and in 28, third tumors developed (5-year incidence rate, 11%; 10-year incidence rate, 22%; median time to third tumor development, 5.8 +/- 8.3 years). The 5- and 10-year survival rates for this group were 41% and 30%, respectively (median survival time, 4.1 +/- 1.0 years). Of 28 patients in whom third tumors developed, 27 (96%) had received radiation therapy for their retinoblastoma. The most common sites for third tumors were soft tissues of the head (36% of all third tumors) and skin (36% of all third tumors). In six patients, a fourth tumor developed, and in two patients a fifth tumor developed. All fourth and fifth tumors were found in the soft tissues of the head, the skin, or the bones. CONCLUSIONS: Survivors of retinoblastoma in whom second malignant neoplasms develop are at a higher risk for the development of additional tumors than they were for the development of a second tumor. The locations and expected ages at which additional tumors develop are consistent with the patterns we have seen in second tumors.     

Abnormal activation in the visual cortex after corneal refractive surgery for myopia: Demonstration by functional magnetic resonance imaging

OBJECTIVE: To try to correlate subjective photophobic symptoms with visual pathway modifications (from the retinal image to the visual cortex) after refractive surgery by exploring brain activation on photic stimulation. DESIGN: Noncomparative case series. PARTICIPANTS: Four subjects reporting discomfort produced by luminance (glare, halos, starbursts, or a combination thereof) in one eye after laser in situ keratomileusis (LASIK) were enrolled. The contralateral myopic eye (control) had no visual impairment and had undergone LASIK without complications or had not had previous surgery. METHODS: Functional magnetic resonance imaging was performed during photic stimulation, delivered by an optical fiber, of the affected and unaffected eyes. RESULTS: Functional magnetic resonance imaging provided evidence that most subjective visual symptoms correlated with anatomic flap abnormalities are associated with a higher signal increase in the visual association cortices compared with a nonsymptomatic eye. CONCLUSIONS: Functional magnetic resonance imaging of the visual cortex may help in exploring the mechanisms involved in glare effects after refractive surgery.     

Cranial nerve damage in patients after alpha (heavy)-particle radiation to the pituitary.

The records of 161 patients were reviewed to determine if radiation damage had occurred following cranial irradiation. All of these patients had received alpha-particle radiation to their pituitary glands during the period when this form of therapy was given for diabetic retinopathy. Extraocular muscle palsy developed in 11 of these patients, iridoplegia in six, and fifth nerve damage in six. All of the palsies developed within a short period following their irradiation, and a definite dose relationship was present. The dose rate was approximately 100 rads/min for all cases. Fractionation varied but it is known for all cases. The estimated doses to the third, fourth, fifth, and sixth cranial nerves was calculated at a saggital plane 13 to 15 mm from the pituitary by using computer-drawn dosimetry charts for the respective aperture size. The energetic alpha particles were produced by the 184-in synchrocyclotron at Berkeley, Calif. A dose relationship for radiation palsies was apparent.     

Therapeutic benefits of infrared (810-nm) diode laser macular grid photocoagulation in prophylactic treatment of nonexudative age-related macular degeneration: two-year results of a randomized pilot study

OBJECTIVE: This pilot study collected preliminary information on the effectiveness and safety of infrared (810-nm) diode laser macular grid photocoagulation in patients with nonexudative age-related macular degeneration (AMD). Results from this pilot study were used in designing a larger, multicenter, randomized clinical trial. DESIGN: A multicenter, randomized, controlled, clinical trial. PARTICIPANTS: A total of 229 eyes of 152 patients with AMD were enrolled in the pilot study. Seventy-five patients with 1 eye eligible (75 eyes) were enrolled in the unilateral arm of the study; 77 patients with both eyes eligible (154 eyes) were enrolled in the bilateral arm of the study. In the unilateral study arm, 32 eyes were randomized to the observation group, 27 eyes were treated with visible endpoint burns, and 16 eyes were treated with invisible endpoint (subthreshold) lesions. In the bilateral study arm, 77 eyes were in the observation group, 36 eyes were treated with visible burns, and 41 eyes were treated with subthreshold (invisible) lesions. INTERVENTION: Eyes were treated with infrared (810-nm) diode laser macular grid photocoagulation using either visible burns or subthreshold (invisible) lesions and compared to eyes receiving no treatment. MAIN OUTCOME MEASURES: Reduction of drusen, change in visual acuity, and rate of choroidal neovascularization (CNV) membrane formation. RESULTS: At 12 months after treatment, 62% of eyes treated with visible burns had a clinically significant reduction in drusen, whereas this proportion (65%) was reached in 18 months for eyes treated with subthreshold lesions. At 24 months' follow-up, treated eyes had a significant reduction in drusen compared to observation eyes (P < 0.0001). Visual acuity was significantly improved in treated eyes at 12, 18, and 24 months compared to observation eyes (P < 0.001). Choroidal neovascularization formation was similar in treated and observation eyes through 24 months' follow-up. Complications included CNV associated with six eyes treated with visible burns and a juxtafoveal laser scar in one eye treated with visible burns. CONCLUSIONS: Infrared (810-nm) diode laser macular grid photocoagulation in patients with nonexudative AMD significantly reduces drusen levels (P < 0.0001) and significantly improves visual acuity (P < 0.001) when either visible endpoint burns or subthreshold endpoint lesions are used. Complications were fewer using subthreshold endpoint lesions. A larger, multicenter, prospective clinical trial with longer follow-up is needed to determine the efficacy of treatment in reducing the rate of CNV formation. Data from this clinical pilot study have been used to design the Prophylactic Treatment of AMD Trial (PTAMD), a multicenter, randomized, prospective clinical trial currently in progress comparing subthreshold (invisible) treatment to observation in eyes with nonexudative AMD.